Capacitance coupler



Nov. 1,1938.

CAPACITANCE COUPLER Filed Apr1.29, 1936 INVENTOR Patented Nov. l, 1938 PATEIW OFFICE CAPACITANCE COUPLER Ralph Higgins, Akron,

Ohio, asslgnork to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Application April 29, 1936, Serial No. 76,953

2 Claims.

This invention r'elates to capacitance couplers for diverting current from an electrical conductor, and particularly to capacitance coupling means associated with bushing insulators.

One object of the invention is to provide a capacitance coupler which will not be materially affected by changes in the surrounding electrostatic eld.

A further object of the invention is to provide a capacitance coupler which shall have substantially constant capacitance for varying weather conditions.

A further object of the invention is to provide a ldevice of the class named which shall be 0f improved construction and operation.

Other objects and advantages will appear from lthe following description.

The invention is exemplified by the combination an arrangement of parts shown inthe aclowing specification, and it is more particularly pointed out in the appended claims.

In the drawing: i

Fig. 1 is an elevation with parte` in section showing a bushing insulator having one embodiment of the present invention applied thereto.

Fig. 2 is a diagram representing the electrostatic iield about a bushing insulator' equipped with a capacitance coupler.

Fig. 3 showsthe variation in this field due to moisture on the surface of the bushing insulator.

Fig. 4 illustrates the operation of the present invention in preventing variation in the electrostatic eld.

In the operation of capacitance devices and particularly in the operation of capacitance couplers, it has been discovered that variationsv in weather conditions change the operation of such devices.

bushing and other insulators with capacitance members for diverting energy from the conductor associated with the insulator. One such device is shown in Fig. 1 of the drawing in which the numeral I0 designates an electrical conductor which extends through a metallic flange II I by a bushing insulator comprising an upper cone or shell I3 and a lower shell cr dome I4. An expansion chamber I5 is mounted on the upper end of the cone I3 and a terminal member V`I6 engages the lower end of the dome I4. The conductor I0 is connected to the terminal I 6 and is Heretofore it has been the pracprovided with a ring nut I1 screwed on thenpper end of the conductor and bearing on the ring I8 which engages a helical spring I9 resting on the base 20 of the expansion chamber I5. By this arrangement, the conductor is insulated irom 6 Supplemental dielectric tubes 23 and 2.4 sur- 10 round the conductor III and are supported from the terminal I6 by a collar 25 and cement 26. An outer dielectric tube or keg 21 surrounds the tube 24 and is supported by an extension 28 on the flange II to which the keg is secured by 15 cement 29. The outer surface of the keg 21 is covered by a metallic coating 39 which terminates at each end in pockets 3| and 32 formed by ilanges 33 and 34 respectively on the outer surface of the keg. The l provided with a springcontact 35 which engages a terminal 36 on a conductor 31, passing through an Youtlet bushing 38 into a flexible casing 39 through which the conductor 31 is led to apparatus to be supplied with lductor I0 through the capacitance coupling formed by the capacitance member 30. Various forms of apparatus may be supplied with energy. in this way.

In the drawing a transformer 38 is shown for 30 connecting the conductor 31 to a voltmeter 39. A resistance 40 is illustrated apparatus. An arcing gap 4I is shown for limiting the voltage to be applied to the transformer 38. It will be understood, of devices other than that illustrated may be supplied With energy through the capacitance coupler. An insulated flux contro142 surrounds the keg 21 above the upper extremity of the extension 28 on the ange II. This control may be silnilar to that described in my prior Patent No. 1,972,590.

44. The capacitance member extends beyond .the ilange 43 and 50 ground sleeve extension 44 as has heretofore been the practice. The electrostatic field is represented by lines drawn from the conductor I0 members 43 and 44.

metallic coating 30 is 20 energy from the con- 25 for adjusting the course, that various 35 trated in Fig. 2, many of the lines of force from the portions of the conductor extendingbeyond the capacitance member 42 will extend to the capacitance member adjacent its ends. Other lines of force further out along the conductor will extend directly to the grounded flange and sleeve. The distribution of the electrostatic iield, when the insulating members I3 and I4 are dry, will be approximately that illustrated in Fig.

2. The lower end oi' the bushing is usually enclosed in a housing so that it is not subject to the weather, but the upper end is frequently exposed and during rain or snow a portion of the cone i3 may be covered with moisture, as shown by the solid line 46. When this occurs, the wet outer surface of the cone becomes a conductor and forms a continuationoi the grounded flange 43 so that the lines of force from the upper end o! the conductor Hi, instead of terminating in the capacitance member 45, will be diverted to the wet surface of the cone I3, as illustrated in Fig. 3. This diversion of the electrostatic lines of force will of course change the capacitance of the coupling formed by the conductor l0 and capacitance member 45 so that for a given voltage on the conductor I0, less energy will be diverted when the insulator is wet than when it is dry.

If the tap 41 is connected with a voltmeter, for instance, this will produce an error in the reading if the connection is calibrated for dry conditions. To avoid this error, the arrangement shown in Figs. 1 and 4 is employed in which a grounded extension is carried inside of the bushing and disposed beyond the end of the capacitance member. This grounded extension comprises the members 28 and 42 in Fig. 1 of the drawing and is illustrated diagrammatically at 48 in Fig. 4 of the drawing. It will be seen from Fig. 4 of the drawing that the electrostatic ileld, which is aiected by the weather conditions, is permanently diverted from the electrostatic coupler 49 which terminates below the extremity of the grounded flange.

In Fig. 1, no provision is made for diverting the lines of force from the lower end of the conductor l0 away from the capacitance member 10 because where the lower end of the bushing is enclosed in the housing, it is of course not subject to weather changes. In the case of 'wall or other bushings where both ends of the bushing may be subject to conditions producing a variable field, corrective means like that shown at one side only of the supporting ilange in Fig. 1 may be applied 'at both sides Of the flange.

I claim:

1. The combination with a bushing insulator having a conductor extending therethrough, of a grounded fitting for said bushing insulator, a capacitance coupler comprising'a capacitance sleeve surrounding said conductor, a portion of saidvconductor extending beyond said sleeve, and a grounded flux control sleeve disposed within said bushing insulator beyond the end of said capacitance sleeve but adjacent thereto and having its inner surface of substantially the saine diameter as the inner surface of said capacitance sleeve, said inner surfaces being arranged in registration with each othersaid flux control sleeve being interposed between said bushing insulator and said conductor for diverting, from said capacitance sleeve, lines of force emanating from a portion of said conductor extending beyond but adjacent to the end of said capacitance sleeve.

2. The combination with a conductor of a grounded support for said conductor having an opening through which said conductor extends, a bushing insulator for supporting said conductor in said opening and for insulating said conductor from said support, a capacitance coupler for diverting energy from said conductor and comprising a capacitance sleeve surrounding saidfconductor, a portion of said conductor projecting from said capacitance sleeve beyond said grounded support, and a grounded flux control sleeve of substantially the same inner diameter as said capacitance sleeve anddisposed beyond but closely adjacent the end of said capacitance sleeve and registering with the end of said capacitance sleeve for diverting, from said capacitance sleeve, electrostatic lines of force emanating from a portion of said conductor adjacent to but extending beyond said capacitance sleeve.

RALPH HIGGINS. 

